Refrigerating apparatus



July 23, 1935. H. B. HULL 2,008,715

REFRIGERATING APPARATUS Original Filed Jan. 51, 1931 44 I ltggNTORZ Z ATTORNEY Patented July 23, 1935:

IPATENT- OFFICE v r REFRIGERATING APPARATUS Harry B. Hull, Dayton, Ohio, assignor, by mesne assignments, to General Motors Corporation, a corporation of Delaware Application January 31, 1931, ,Serial No. 512,631

Renewed September 13, 1933 19 Claims. (01.52-115) This invention relates to refrigerating apparatus and more particularly to the compression type of such apparatus.

In refrigerating apparatus of the compression type, it is customary to connect the high pressure or discharge .side of a compressor to condenser-and to connect the low pressure or inlet side thereof to an evaporator, the discharge side 'of the condenser being in turn connected to'the inlet side of the evaporator. Systems of this type are provided with a body of lubricant, such as lubricating oil, for lubricating moving elements of the compressor. This body of lubricant is stored usually in the compressor crankcase.

which provides a reservoir therefor and which is in communication with the inlet of the compressor; In systems of this type where a lubri-- low pressure side of the system is permitted to rev turn to the oil reservoir during off cycles of the system that considerable refrigerant is absorbed in the body of oil. Additional refrigerant there after enters the reservoir, some of which is further absorbed in the oil and some of which tends to build-up pressures therein. It has also been found when they pressure upon the lubricant thus charged with refrigerant, is quickly reduced by operation of the compressor, that considerable frothing or foaming takes place in the oil reser voir which'oauses some of the foaming oil to be pumped to other parts of the system to thus affect the efliciency of the system. In so doing a por- .tion of the lubricant is withdrawn from where it is required for the lubrication of the compressor parts. v

One of the objects of this invention is to provide means for controlling the admission of refrigerant to the oil reservoir to thereby prevent absorption in the body of oil and to also prevent the building up of pressures in said reservoir during periods of inoperativeness of the compressor. .Another object is to provide improved means for preventing, to any appreciable extent, the.

circulation of lubricant throughout the refrigerating system.

Further objects and advantages of the present larged view of" the compressor partly in crosssection and partly in elevation.

Referrlng to the drawing the numeral 20 designates in'general a refrigerating syste'm embodying features of my invention. The system 28 includes a compressor 22, condenser 23, receiver 24; and evaporator v25. A motor 26 is provided for driving the compressor 22. v Refrigerant flows through the parts in the order named. That is, refrigerant is compressed in the compressor, dis- 19 charged through conduit 30 into the condenser wherein it is liquefied and from which it passes to the receiver 24. The receiver 24' is connected to evaporator 25 by means of a liquid supply conduit 32. The liquid refrigerant in the evaporator 25 vaporizes to produce a cooling efiect and the vapors pass from the evaporator through a vapor conduit 34 to the crankcase of the compressor in a manner described hereinafter. The motor 26 is connected todrive the compressor, and in order to provide means for starting and stopping the motor in response to predetermined high and low pressure conditions within the evaporator I have provided an automatic switch 35. Swith 35 is op-- erated by bellows 36 which is responsive to pressure within the vapor conduit 34. The motor and compressor are controlled in response to predetermined high and low pressure conditions within the evaporator. In view of the fact that pressure conditions within the evaporator vary directly with the temperature conditions therein the motor compressor unit is in reality'responsive to the temperature conditions within the evaporator. The evaporatormay be of any desired type, and

for instance, it'may 'be of the float controlled flooded type similar to'that described in the patent to R. G. Osborne, No. 1,556,708, patented October Referring more in detail to the drawing, the

compressor 22 includes a casing 40 which provides 40 a crankcase portion 42 forming a reservoir for lubricating oil. The lower portion of the .casing 40 is closed by plate 43 which is secured} thereto by screws 44. The upper portion of the casing 40 provides a cylinder portion 45 in which recip- 45 rocates a piston 48 actuated by pitman 49 which in turn is actuated by eccentric 50' carried by a drive shaft 52. The drive shaft 52, to which is secured the counter-balancing weight 55, is journaled in opposite aligned bearings 51 and 58 50 formed in the wall of the casing 40. The shaft 52 extends outwardly through'the casing 40- and has secured thereto a flywheel pulley 60 over which pulley is adapted to pass a belt driven in the usual way by the motor 26; The compressor also 'in- 55 7 leads to the crankcase of said compressor. The

. pressor.

' p p through a strainer I04 with the body of oil in the admission of refrigerant to the crankcase is controlled by a valve which permits said refrigerant to pass from conduit 34 to said crankcase through inlet I0, groove 82 in valve 80 and passage only during operation of the compressor. 6 Thus as the compressor operates, refrigerant in vapor or gaseous form, is drawn through conduit 34 and inlet I0 into the crankcase of the compressor.

Means are provided for lubricating the com- The means for lubricating the compressor includes the body of oil in the crankcase. and an oil pump I00 having its inlet side below the level of oil in the crankcase and its discharge side connected to various ducts leading to the bearings and wearing surfacesof the compressor. The oil pump is of the eccentric typeiand is actuated by;

the drive shaft 52. A conduit- I02 communicates at one end with the inlet passage I03 to the oil I00 and at its other end communicates crankcase of the compressor. A passage I06 in the drive shaft communicates with the chamber I08 into which chamber the oil pump discharges,

and lateral passages I0I, in communication withthe passage I06 in the drive shaft, are provided for conveying lubricant to the bearings 51 and 58. A passage H0 is providedinthe pitman 49 for supplying lubricant to the piston pin II5. Thus various moving elements of the compressor are lubricated by a forced feed lubricating system, the lubricant being withdrawn from the crankcase of the compressor and forced by the oil pump I00 to the various passages to the wearing surfaces of the compressor.

In order to prevent gaseous refrigerant from entering the crankcase of the compressor during periods of idleness of the compressor the valve 80 has been provided. The valve 80 is arranged so that refrigerant can pass to the crankcase of the compressor during the operation of the compressor and is arranged for closing the inlet to said crankcase when the compressor is inoperative. Any suitable means may be provided for controlling the valve 80. However, I prefer to employ the means used for lubric ting the compressor. The valve 80 is slidably 'sposed in bore I20 provided in boss I5. The val e 80 is provided with the annular groove 82 whi h is adapted to be in aiignment with the compressor inlet during the operation of the compressor and is adapted to be out of alignment with said inlet when the compressor is inoperative. The valve operates as follows: During operation of the compressor, the pressure in chamber I08 forces some oil through passage I25 into chamber I30. The oil under pressure in chamber I30 acts on the bottom of valve 80 and causes it to be raised upwardly against the action of spring I33 until the groove 82 is in alignment with the compressor inlet. Any further upward movement of valve 80 is prevented by a relief passage I35 which permits the oil under pressure in chamber I30 to pass therethrough to thus return to the oil reservoir. A by-pass I40 is provided to relieve any pressure which might build up in bore I20 above valve 80 when said valve is being urged upwardly by the lubricating means.

When the compressor ceases operation, the

pressure in chamber I 30 recedes to thus permit the valve 80 to be moved downwardly under the influence of spring I33 to thus close the inlet to the compressor crankcase. A stop I40 is provided to limit the downward movement of valve 80.

As a further precaution against foaming or frothing in the crankcase a screen I50 is provided. The screen is of a very fine wire mesh and is placed above the level of oil in the crankcase. In most instances the screen is unnecessary, but where a refrigerant which is miscible to any appreciable extent is used in the system said screen may be used, if desired.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form,

it is to be understood that other forms might be adopted, all coming within the scope of the claims preventing refrigerant from said evaporator from entering said reservoir during periods of idleness of said compressor.

2. A closed refrigerating system comprising in combination a compressor, condenser and evaporator, said compressorhaving a high pressure side communicating with said condenser and a low pressure side communicating with said evaporator, a volatilerefrigerant in said system, said compressor providing a reservoir for lubricant on the low pressure side of said compressor and communicating with said evaporation a quantity of lubricant in said reservoir miscible with said refrigerant, and means independent of the pressures within said closed refrigerating system for preventing the absorption of refrigerant by the lubricant during idle periodsof the compressor.

35A closed refrigerating system comprising in combination a compressor, condenser and evaporator, said compressor having ahigh pressure side communicating with said condenser and a low pressure side communicating with said evaporator, a volatile refrigerant in said system, said compressor providing a reservoir for lubricant on the low pressure side of said compressor and communicating with said evaporator, a quantity of lubricant in said reservoir miscible with said refrigerana and means controlled by the pressure of the lubricant for preventing the absorption of refrigerant by the lubricant during idle periods of the compressor.

4. A closed refrigerating system comprising in combination a compressor, condenser and evaporator, said compressor having a high pressure side communicatingwith said condenser and a. low pressure side communicating with said evaporator, a volatile refrigerant in said system, said compressor providing a reservoir for lubricant on the low pressure side (of said compressor'a'nd communicating with said evaporator, a quantity of lubricant in said reservoir miscible with said refrigerant, lubricating means for said compressor and means operable in response to the operation of said lubricating means for controlling the flow of refrigerant from said evaporator to said reservoir for preventing the absorption of refrigerant by the lubricant during idle periods of the compressor.

' 5. A closed refrigerating system comprising in combination a compressor, condenser and evaporator, said compressor having. a high pressure side communicating with said condenser and a low pressure side communicating with said evaporator, a volatile refrigerantin said system, said compressor providing a reservoir for lubricant on the low pressure side of said compressor and communicating with said evaporator, a quantity of lubricant inv said reservoir miscible with said refrigerant, lubricating means for said compressor, and a valve operable in response tothe operation of said lubricating means for admitting refrigerant from said evaporator to said reservoir for preventing the absorption of, refrigerant by the lubricant during idle periods of the compressor.

6. A closed refrigerating system comprising in a combination a compressor, condenser and evaporator, said compressor having a. high pressure side communicating with said condenser and a low pressure side communicating with said evaporator, a volatile refrigerant in said system, said compressor providing a reservoir for lubricant on the low pressure side of said compressor and communicating with said evaporator, a quantity of lubricant in said reservoir miscible with said refrigerant, and means responsive to pressure created by the operation of said compressor forcontrolling the admission of refrigerant to said reservoir.

'7. A closed refrigerating system comprising in combination a compressor, condenser and evaporator, said compressor having a high pressure side communicating with said condenser and a low pressure side communicating with said evaporator, a volatile refrigerant in said system, said compressor providing a reservoir for lubricant'on the low pressure side of said compressor and communicating with said evaporator, a quantity of lubricant in said reservoir miscible with said refrigerant, lubricating means for said compressor, and means responsive to the operation of said lubricating means for controlling the admission of refrigerant to said 1 reservoir for preventing the absorption of refrigerant by the lubricant during idle periods of the compressor.

8. A closed refrigerating systemcomprising in combination a compressor, condenser and evaporator, said compressor having a high pressure side communicating with said condenser and a low pressure side communicating with said evaporator, a volatile refrigerant in said system, said compressor providing a reservoir for lubricant on the low pressure side of said compressor and. communicating with said evaporator, a quantity of lubricant in said reservoir miscible with said refrigerant, lubricating means for said compressor, and a valve responsive to the operation of said lubricating means for controlling the admission of refrigerant to said reservoir for preventing the absorption of refrigerant by the 1dbricant during idle periods of the compressor.

9. A closed refrigerating system comprising in combination a compressor, condenser, and evaporator, said compressor having a high pressure side communicating with said condenser and a low pressu'e side communicating with said evaporatir, a volatile refrigerant in said system, said compressor providing a reservoir for lubricant on the low pressure side of said compressor and communicating with said evaporator, a quantity of lubricant in said reservoirmiscible with said refrigerant, and a fine screen extending across said reservoir-above said lubricant dividing said lubricant in the lower portion of the reservoir fromrefrigerant in the upper portion of said reservoir.

10. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said system containing a volatile refrigera'nt and being provided with a reservoir for a lubricant which is at least partially miscible in the refrigerant, said reservoir being within the system and exposed at times to the refrigerant, and means dependent upon the stopping of the compressor for preventing refrigerant from entering said reservoir during idle periods of the compressor.

11. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said system containing a'volatile refrigerant and being provided with a reservoirfor a lubricant which is at least partially miscible in the refrigerant, said reservoir being within the system and exposed at times to the refrigerant, and means including a pump operated by the compressor for preventing refrigerant from entering said reservoir during idle periods of the compressor.

12. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said system containing a volatile refrigerant and being provided with a reservoir for a lubricant which is at least partially miscible in the refrigerant, said reservoir being within the system and exposed at times to the refrigerant, and means including apumpoperated by the compressor for separating the refrigerant in the'evaporator from the lubricant in the reservoir during idle periods of the compressor.

13. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said system containing a volatile refrigerant and being provided with a reservoir for a lubricant, which is at least partially miscible in the refrigerant, said reservoir being within the system and exposed at times to the refrigerant, and means including a pump operated by the compressor and a valve means for separating the refrigerant in the evaporator from the lubricant in the reservoir during idle periods of the compressor.

14. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said system containing a volatile refrigerant and being provided with a reservoir for a lubricant, which is at least partially miscible in the refrigerant, said reservoir being within the system and exposed at times to the refrigerant, and means controlled by the lubricant for separating the lubricant from the refrigerant in the evaporator during idle periods of the compressor.

15. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said compressor having a high pressure side communicating with said condenser and a low pressure side communicating with the evaporator forming a high side and a low side of the system, a volatile refrigerant in said system, said system having a reservoir for lubricant on the low side thereof exposed at least at times to the refrigerant, said refrigerant being at least partially miscible with the lubricant, and means for preventing the absorption of refrigerant by the lubricant during the idle periods of the compressor.

16. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said compressor having a high pressure side communicating with said condenser and a low pressure side communicating with the evaporator forming a high side and a low side of the system, a volatile refrigerant in said system, said system having a reservoir for lubricant on the low side thereof exposed at least at times to the refrigerant, said refrigerant being at least partially miscible'with the lubricant, and means operative during the stopping of the compressor for preventing the entrance of refrigerant to the lubricant reservoir during idle periods of the compressor.

17. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said compressor having a high presrefrigerant, said refrigerant being at least partially miscible with the lubricant, and means for preventing the entrance of refrigerant from the evaporator to the lubricant reservoir during the entire idle period of the compressor.

18. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said compressor having a high pressure side communicating with said condenser and a low pressure side communicating with the evaporator forming a high side and a low side of the system, a volatile refrigerant in said system, said system having a reservoir for lubricant on the low side thereof exposed at least at times to the refrigerant, said refrigerant being at least partially miscible with the lubricant, and means for preventing the absorption of refrigerant by the lubricant during the entire idle period of the compressor.

19. A closed refrigerating system comprising in combination a compressor, a condenser, and an evaporator, said compressor having a high pressure side communicating with said condenser and a low pressure side communicating with the evaporator forming a high side and a low side of the system, a volatile refrigerant in said system, said system having a reservoir for lubricant on the low side thereof exposed at least at times to the refrigerant, said refrigerant being at least partially miscible with the lubricant, and means for preventing the entrance of the refrigerant to the lubricant reservoir during the entire idle period of the compressor.

HARRY B. HULL. 

